Superabsorbent water-resistant coatings

ABSTRACT

Articles coated with a water-resistant coating that absorbs water to provide the water-resistant effect, and desorbs water when the coating is dried, and a method of providing water resistance and corrosion resistance to articles prepared with such coatings. The coating is formed by applying a composition comprising an aqueous solution of a superabsorbent water-soluble polymer precursor, optionally a viscosity modifying agent, and optionally a lubricant onto the surfaces of the article, and curing to form a coating comprising the superabsorbent polymer.

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION

[0001] This application is filed as a continuation-in-part ofapplication Ser. No. 09/190,866, filed Nov. 13, 1998.

[0002] The present invention relates to a high strength superabsorbentcoating capable of rapidly absorbing water, which is suitable forcoating a variety of articles requiring a water-resistant surface,including, but not limited to, reinforced or molded products, as well asreinforcing materials used in the manufacture of such products. Morespecifically, the coating is formed from a composition comprising asuperabsorbent polymer precursor that, upon curing, forms a polymer witha high water swelling ability; and a film-forming polymer. The coatingcomposition may further include a viscosity-modifying agent.

[0003] The inventive concept also relates to articles coated with thesuperabsorbent coating composition, including reinforced and moldedproducts and fibrous reinforcing materials; as well as methods ofapplying such coatings. The coating of this invention demonstrates ahigh level of water absorption in fresh and salt-water environments, andexcellent spreading and coating ability when applied to a substrate.

BACKGROUND OF THE INVENTION

[0004] Deterioration caused by the invasion of moisture beneath theexposed surfaces of articles used in outdoor environments is awell-known problem. This deterioration includes oxidative deteriorationcaused by reaction of water with the surfaces of reinforcing fibers usedin these articles, as well as water-induced corrosion. In marineenvironments, for example, the problems associated with waterlogging areparticularly compounded by the salinity of the environment. The presenceof salt in such aqueous environments hastens the oxidativedecomposition. In non-saline environments, for example in environmentshaving high atmospheric humidity, water-resistant coatings are necessaryto protect the structures and equipment surfaces from moisture-induceddecomposition.

[0005] Articles affected by the deterioration described above includeitems having a surface exposed to high moisture or humidity. Examples ofsuch articles include reinforced rods and cables, such as fiber optic ortelecommunications cables. These telecommunications cables are oftenused in situations where they are buried underground or submerged inwater over long periods. As such, protection from water damage iscritical to the structural integrity of these cables and to the successof the functions they are intended to perform. A telecommunicationscable, for example, may include a core comprising a glass rod that actsas a stiffening or reinforcing member. This rod contributes to therigidity of the cable. When water penetrates to contact the core elementof the cable, corrosion or chemical deterioration of the cableinfrastructure may result.

[0006] In order to combat the problems associated with this waterloggingdamage, several strategies have been devised in an attempt to providewater resistance to cables and other reinforced articles, and to protecttheir sensitive inner surfaces from contact with water or water vaporpresent in the surrounding environment. These techniques for makingwater-repellent articles have included wrapping the articles in aprotective sheathing material; or sealing the surface to be protected.Sealing techniques may include chemically manipulating the surface layerof the article to render it resistant to water-absorption, or applying arepellent coating.

[0007] The technique of covering the surface with a protective sheathingmaterial is conventional. It includes for example, using a wrap or tapemade of an impervious polymer with water-blocking ability, or treatingthe wrapping material with an emulsion or solution of a water-blockingpolymer. The sheathing process does not require application of achemical compound or treatment to the surface of the article, rather theprotection is derived only from the coverage by the sheathing material.

[0008] Coatings used to repel water traditionally have been composed ofsubstances that are both insoluble and impenetrable to water, andtherefore presented a physical barrier to encroaching moisture. Suchbarrier coatings have included materials such as greases or gels. In thecase of cables, for example, these coatings are applied by extrusionunder pressure. There are however, certain drawbacks associated withthis type of coating. Greases or gels are difficult to handle because oftheir slipperiness, and they contribute an unpleasant feel to the coatedarticle. This is an important factor to be considered in themanufacturing process, particularly because it affects the ease ofhandling of the cable during splicing operations. Greases and gels alsoundergo changes in viscosity at low or high temperatures. Theseviscosity changes may affect the freeze/thaw performance and thereforethe stability of the coating. Poor performance in these respectstherefore affects the stable performance of the cables.

[0009] More recently, greaseless, water-resistant dry coatings have beendevised which, of themselves, have some degree of water-absorbingcapacity. This ability to absorb water allows the coating to absorb themoisture contacting the article, while preventing direct contact withthe sensitive surfaces. The absorbent component in these drywaterblocking coatings is a dry, granulated superabsorbent polymer thatswells and absorbs upon contact with water. The superabsorbent polymersare usually characterized in terms of their swell rate, swell capacityand gel strength. Traditional uses for these dry superabsorbent polymershave primarily included personal hygiene product articles, foodpackaging articles and chemical spill cleanup compositions, howeverrecent experimentation has included using these dry polymers to formcoatings for other articles such as reinforced cables. For example, U.S.Pat. No. 5,689,601 to Hager, which is herein incorporated by reference,discloses a dry waterblocking coating for reinforcing fiber articlesusing a powdered or granulated water-soluble dry blocking ingredientencased in one or more thin layers of a sheathing polymer. This casingrestricts the degree of water absorption that can be achieved by thegranular polymer, and accordingly the swell capacity of this coating islimited.

[0010] The superabsorbent polymers traditionally used in drywaterblocking cable coating applications are dry, water-insoluble,granular polymers that are incorporated into various substrates such asyarn, binders and tape. The substrates typically also contain glassfibers as a form of reinforcement. However, as discussed above, thecoatings formed with dry granulated blocking agents suffer thelimitations of limited water swelling ability and swell rate as anecessary consequence of optimizing the gel strength. In the context ofsurface coatings, gel strength is defined as the ability to preventwater from wicking down the cable axis, particularly when the cables areused in aqueous environments where they are exposed to elevated waterpressures. The swelling ability is directly related to the degree ofcross-linking of the superabsorbent polymer. As the degree ofcross-linking increases, so does the gel strength, but there is arelated decrease in the swell rate and swell capacity of the polymer.The swell rate defines the amount of water that the coating absorbs overa fixed period of time. The swell capacity denotes the maximum amount ofwater or fluid absorbed by the coating, based on a measure of its dryweight. Consequently, coatings made of dry, granular, water-insolublepolymer are limited in their water-absorbing performance, as measured interms of the swell rate and swell capacity.

[0011] Generally, coatings for reinforced fibers, strands and articlessuch as cables that are made from these fibrous materials are applied tothe surface of the fibrous material and then cured before furtherprocessing, if any, occurs. The means of applying coatings, in general,differs depending on whether a fluid coating is used or whether a solidparticulate coating is being applied. In the case of powdered coatings,the coating process using granulated water-blocking agents involvesseveral time-consuming and labor- and equipment-intensive steps that aredirectly related to the use of a granulated polymer. These steps includethe need for one or more treatments with a binding resin, and one ormore applications of powdered resin at the powder-coating stations usingapparatus such as a fluidized bed.

[0012] The means for applying fluid coatings may include flooding, ordipping the fibers or cables, for example, in a resin bath and thenremoving excess resin to form a consistent layer on the treated surface.In the case of strands, rovings or cables, the product is in the form ofa continuous filament and therefore it can be passed through a stripperdie to remove the excess resin. Alternatively, the coating may besprayed onto the surface of the article. In order to form a coatinglayer that is thick enough to provide good coverage and protection fromwater penetration, the coating composition must be thick enough that itcan adequately coat the article in one pass through the coatingapparatus. In addition to thickness however, the composition must alsohave sufficient flowing ability to allow ready formation of a uniformcoating on the surface of the article, and to prevent clogging of thecoating apparatus, dye orifices or other machinery used to makepolymer-coated fibrous articles. Traditionally in the art, in order tomodify the viscosity of the fluid coating composition, dry particulateingredients such as a flocculent polymer or starch have been used. Thedifficulty with such compositions is that the resulting compositionafter this solid ingredient is added is not homogenous. Rather, thecomposition contains varying levels of a particulate material, whichmakes handling difficult and also compromises the spreadability of thecomposition.

[0013] There exists in the art then, a need for a waterblocking coatingcomposition for application to reinforced articles or reinforcingmaterials, which possesses excellent gel strength and wicking ability,as well as a high degree of water absorption and a concurrent, rapidswell rate. At the same time, a further need exists in the art for acoating composition that does not contain powdered polymer, and which,as a result, would not require a costly and labor intensive applicationprocess. Moreover, it is desired that such a coating composition exhibitgood spreading and surface performance characteristics.

SUMMARY OF THE INVENTION

[0014] It has now surprisingly been discovered that highly absorbentwaterblocking coatings having an excellent water swelling capacity and arapid swell rate can be formed by incorporating a solution of asuperabsorbent polymer precursor into an aqueous solution used to coatfibrous reinforcing materials and articles comprising one or morereinforcing fiber materials. The polymer precursor, when cured, forms asuperabsorbent polymer. The coatings containing this superabsorbentpolymer are capable of substantially instantaneous water absorption whenexposed to aqueous environments.

[0015] Depending on the intended application, the superabsorbent coatingmay be enhanced by adding a viscosity-modifying agent. For example,where the coating composition is applied to rods or cables comprisingglass, carbon, polymer or mixtures thereof, including a viscosifierimparts excellent spreading ability to the formulation. Where thearticle being coated is a more pliable product which allows dipping orspraying as a means of application, the viscosity of the coatingformulation may be reduced to allow application by these or similarmeans.

[0016] In another aspect, this invention also relates to a process offorming a coating onto the surface of an article such as afiber-reinforced molded product, or onto the surfaces of a fibrousreinforcing material. Generally, this process includes the steps ofapplying the coating composition to the surface of the fibers, strandsor articles, passing it through a stripper die to remove excess coating,followed by a drying or curing step.

[0017] The inventive concept further relates to articles containingreinforcing fibers that are treated using the water-absorbent coatings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0018] The composition of this invention is suitable for forming asuperabsorbent coating on the surface of articles or materials requiringsurfaces that are resistant to water, and therefore protects thematerial underlying the surfaces that are treated with the coating.

[0019] The term “article”, as it is used herein, is specificallyintended to include any product or material having a surface thatrequires a water-resistant coating to protect the underlying structurefrom deterioration caused by exposure to moisture. Such articles includemolded articles including fiber reinforced composite articles,laminates, sheets, reinforcing fiber materials known in the art, andproducts made using one or more of these fiber materials, eithercollectively or dispersed within a matrix of any type. The term alsoincludes articles manufactured using reinforced fiber products, such asstructural materials or in equipment.

[0020] The articles that may be coated with the compositions of thepresent invention may include fibrous reinforcing materials such asglass, polymer, carbon, natural fibers, or blends thereof. Preferably,the polymer fibers comprise one or more fibers selected from the groupconsisting of aramid fibers, nylon fibers, kevlar fibers, polyesterfibers, polyethylene fibers, polypropylene fibers and combinationsthereof. These fibrous materials may be used in the form of fibers,strands or rovings, either in continuous form or as chopped fibers,strands, or pellets; tapes, mats and fabrics comprised of glass, polymeror natural fibers; composites such as pultruded rods or cables,laminates and other molded articles. Also, the coating can be applied tothe surfaces of articles requiring a surface that is resistant to waterpenetration, such as corrugated metallic tubes and tapes used for rodentprotection in fiber optic cables. Moreover, the superabsorbent coatingmay be applied to the surfaces of article that do not containconventional reinforcing materials, but which would nonetheless benefitfrom the excellent water-absorbing protective properties of the coating.For example, molded articles, woven fabrics, scrims, wood and paperproducts, and construction materials such as steel beams are among themany articles that may be protectively enhanced by application of thepresent invention.

[0021] In one embodiment, the articles for coating according to theinvention include articles that comprise a reinforcing fiber material asat least one component thereof. Examples include articles formed in apultrusion operation. For example, the coatings of this invention can besuccessfully applied to a pultruded rod or cable comprised at leastpartially of reinforcing glass fiber/polymer composite. The polymersthat may be used to form these pultruded articles include thermosettingresins, such as epoxies, polyesters and vinyl esters. The polymercomponent of the pultruded article may also be a thermoplastic resinthat has been heat-treated, however a thermosetting resin is preferred.As an example, a thermosetting epoxy resin such as a vinyl ester may becombined with glass strands in a pultrusion operation to form a rod thatcan be used as the stiffening member in a telecommunications cable.

[0022] As another embodiment, examples of fibrous reinforcement productsin the first category mentioned above include strands or rovings madefrom fiber-forming materials such as glass, carbon, polymers or mixturesthereof. The coating formulation for these products will preferablyinclude a small amount of a lubricant.

[0023] The water resistant properties of the coatings of the presentinvention are obtained by combining a solution of a non-toxic,environmentally safe superabsorbent polymer precursor with the binderresin used to coat the substrate articles. The superabsorbent polymerformed by this precursor possesses a surprisingly high capacity forabsorbing water, and at the same time maintains a high gel strength inthe cured coating as a result of increased cross-linking. As mentionedpreviously, this polymer uniquely provides water resistance by absorbinglarge quantities of water. As water contacts the coated surface of thearticle to be protected, the coating absorbs water and swells in volume.By absorbing the water, the coating effectively wicks away the moistureand thus prevents it from contacting the inner surfaces of the protectedarticle. As a result, the sensitive inner surfaces remain dry and areprotected from waterlogging deterioration. The coatings of thisinvention uniquely achieve water resistance protection by absorbingwater to prevent moisture penetration beneath the coating layer. Thisfunction is distinctly different from the type of protectionaccomplished by the barrier coatings more commonly known in the art,which protect the substrate by forming an impermeable barrier.

[0024] The non-toxic, environmentally safe superabsorbent polymerprecursor used in the coatings of this invention may be selected fromany such polymer capable of forming an aqueous solution for use in thecoating mixture, and which, upon cure, has a swell capacity and swellrate that enables rapid absorption of large amounts of water followed bydesorption without loss of the polymer itself when the coating is dried.A polymer precursor suitable for use in the present coating willdemonstrate a swell capacity of up to about 400 times its initial dryweight when the coating is applied to reinforcing fibers or strands andcured.

[0025] The superabsorbent polymer precursor for use in the presentinvention may, for example, be selected from the group of water-solublepolyacrylates possessing the required ability to absorb and desorb largequantities of water, as has been previously mentioned. Thesuperabsorbent polymer precursor is preferably used in its anionic formas a salt of a corresponding alkali or alkali metal salt. The polymersalt is in the form of an aqueous solution that is either clear orslightly cloudy in appearance. A desirable solids content is in therange of from 30-35% weight. The solution also has a specific gravity ofabout 1.1 grams per milliliter and a viscosity of about 1000 mPas atabout 20° C. The solution is typically slightly anionic, having a pH offrom about 6 to about 8. One example of an acceptable superabsorbentpolymer precursor is a water-soluble anionic polyacrylate in aqueoussolution. It is conceivable that coatings comprising the high swellingsuperabsorbent polymer of the present invention would absorbsignificantly higher quantities of water, demonstrating swell rates upto and including 600 times the dry weight.

[0026] A viscosity-modifying agent may also be added to the coatingcomposition. The role of this viscosifier is to create a spreadingconsistency that will enable adequate coating of the article. Forexample, in the coating of pultruded articles, the coated article isoften passed through a stripper die. Therefore, the viscosity should besufficient to provide good flowing ability and to prevent clogging ofthe coating apparatus and die orifices. The viscosity-modifying agent isnot an insoluble powdered component, rather it is a polymeric solutionor dispersion that can be easily incorporated into the coatingcomposition. Hence, unlike waterblocking coatings previously known inthe art, the coating composition of this invention is in the form of atrue solution having substantially no particulate components. Viscositymodifying agents capable of forming a true solution, such as alkylcellulose or acrylamide polymers, may be used in the coatings of thisinvention. A preferred viscosifier for use in the present coatings is apolyacrylamide in aqueous solution. The polyacrylamide solution isparticularly suitable because of its compatibility with thesuperabsorbent polymer precursor solution and the film-forming bindercomponent.

[0027] The binder component used in the coating compositions of thisinvention can include any polymeric material customarily used as abinder in coating compositions for reinforced fiber-containing products.The binder preferably comprises a film-forming polymer or polymer latexthat is a thermosetting resin or a thermosetting resin with somethermoplastic properties to enhance the flexibility of the coating. Thefilm-forming binder is also necessarily compatible with thewater-absorbing polymer and with the viscosity-modifying agent, in thatit promotes combination of the ingredients in the coating composition,and also facilitates adherence of the coating to the surface once it isapplied. The film-former further provides a tough film with preferablyno surface tackiness or flaking of the coating after it is cured. Thefilm-forming polymer comprised in the binder may for example be apolyester, urethane, epoxy, latex or mixtures thereof. The latex may inturn be selected from an acrylic latex, a styrene-butadiene latex, ormixtures thereof. Preferably, the binder is a film-forming urethane thatpromotes adherence of the water-absorbing polymer to the treated surfaceafter it is dried. An example of a desirable film-forming binder isWitcobond W320, which is a polyurethane film-former available from WitcoChemical Co.

[0028] Optionally, the coating composition may also include one or moreadditives selected from the group consisting of lubricants and wettingagents. Lubricants are added to enhance the handling of thepolymer-impregnated strand in subsequent processing. Where the coatingis applied to fiber reinforcements such as glass strands, a lubricant ispreferably added to reduce stiffness of the strand which enhances therate of water absorption.

[0029] The wetting agent is added to facilitate contact between thedispersion and the fiber surface. Any conventional wetting agent that iscompatible with the other ingredients of the sizing composition can beused.

[0030] When the coatings of the invention are applied to the surfaces ofreinforcing fiber strands and cured, they demonstrate a swell capacityof from about up to about 400 times the initial dry weight of thewater-swellable polymer. Preferably, the swell capacity for this type ofapplication is from about 200 to about 400 times the initial dry weightof the water-swellable polymer. Where the coatings are applied and curedon the surface of articles such as rods or cables, the swell capacityranges up to 120 times the initial dry weight of the water-swellablepolymer. In this context, preferably the swell capacity is from about 50to about 100 times the initial dry weight of the water-swellablepolymer.

[0031] The swell rate of the coating should also be high. The coatingsof this invention demonstrate an exceptionally high swell rate, in theorder of from about 50 grams water to about 340 grams (about 300% toabout 2000%) weight in the first minute, based on the total weight ofthe polymer and the fiber substrate, where deionized water is used forexample, to simulate a fresh-water environment. The swell rate may varyslightly from this range depending on the presence of ionic species orother additives in various fresh water environments. However, generally,in fresh water, the swell rate is higher than can be achieved in asaline solution such as a marine environment. In a saline environment,for example, the rate of water uptake varies depending on the salinityof the aqueous environment in which the coating is used. Typically, thecoatings of the invention demonstrate an absorbency of between about 33grams salt water per gram and about 66 grams salt water per gram (about300% to about 760%), in the first minute. However, whether the coatingis used in either a fresh or salt-water environment, its performance, asmeasured by the swell rate, is demonstrably higher than has beenpreviously achieved by dry waterblocking coatings known in the art. In apreferred embodiment, the water resistant coating of the invention hasthe ability to absorb either about 126 grams of deionized water per gramof dry coating, or about 50 grams of salt water per gram of dry coating,in the first minute of exposure.

[0032] In the method of making the coating compositions of thisinvention, the ingredients are combined in liquid form to prepare thecoating solution. A solution of the superabsorbent polymer precursor isfirst stirred to ensure homogeneity, then added to a mixing tank.Deionized water is then added to the tank, and the lubricant, ifdesired, is then introduced. Next, the polyurethane in the form of anaqueous emulsion is pumped into the tank. The viscosity-modifying agentis first premixed to form a 1% wt. aqueous solution, and a sufficientamount of this aqueous solution is added to the mixing tank. As a finalstep, the mixture is then stirred, without heating, and the resultingcomposition is ready for application.

[0033] The composition is contacted with the surface of the articles tobe coated by a means suitable for applying a liquid coating. Forexample, the coating composition can be applied by passing reinforcingfiber strands through a resin bath. Alternatively, the composition isapplied to an article to be coated by spraying, flooding, or by anyother means which permits the liquid coating to be contacted with theentire surface of the article. A further processing means may then beused to ensure an even and adequate distribution of the coating layer.For example, fiber strands or rods coated with the coating compositionare passed through a stripper die. The coated articles are then driedand cured. The article coated with the superabsorbent polymer precursorcan be heated to 212° F. (100° C.) for a period sufficient to volatilizea substantial portion of the water. The polymer precursor-coated articleis then heated to approximately 280° F. (138° C.) to cure the polymer bycross-linking. Typically, polymers heated to above approximately 300° F.(149° C.) lose the desired superabsorbent quality. The drying/curingstep may be performed in an in-line oven. In a 38 foot (11.58 meters)long oven set to approximately 600 ° F. (316° C.) the polymer is curedat 380-490 feet (115-149 meters) per minute, and preferably at 440-465feet (134-142 meters) per minute.

[0034] Glass fiber reinforced articles having the water resistantcoating herein described may be used in applications where exposure towater or water vapor is likely, and where the formation of a durable,resilient, flexible coating with good waterproofing properties isdesired. The following examples are representative, but are in no waylimiting as to the scope of this invention.

EXAMPLES

[0035] Exemplary coating formulations were prepared by combining afilm-forming binder polymer, a water-absorbing polymer precursorsolution and a polyacrylamide solution. The coating compositions werethen applied to pultruded glass-vinyl ester rods using a floodingprocess. After the coating composition was applied, the rod was passedthrough a stripper of desired orifice size to control the amount ofcoating composition deposited on the surface of the rod. The rod wasthen heated to volatilize the water component, then further heated toabout 270° F. (132° C.) to cure the coating and activate thesuperabsorbent polymer precursor.

Example 1

[0036] In this example, a coating composition for treating pultrudedglass/polymer rods was formulated by mixing the ingredients in theproportions listed below:

[0037] 33.3% weight of a superabsorbent polyacrylate precursor solution(aqueous), available commercially as Stockhausen Cabloc FL fromStockhausen Inc. or Product XP-99.01 from Emerging Technologies Inc.(ETI);

[0038] 25.0% weight of a urethane film-forming polymer, Witcobond W290H,available from Witco Chemical Co.; and

[0039] 41.7% weight of a 1% wt. aqueous acrylamide solution, Drewfloc270, which is available commercially from Ashland Chemical Inc.

Example 2

[0040] In this coating composition for pultruded rods, the ingredientswere combined as follows:

[0041] 28.6% weight Stockhausen 63815 superabsorbent polyacrylateprecursor solution;

[0042] 35.7% weight urethane film-forming polymer, Witcobond W320,available from Witco Chemical Co.; and

[0043] 35.7% weight of a 1% wt. aqueous solution of Drewfloc 270.

Example 3 Water Resistance Testing

[0044] An exemplary coating composition was developed according to thefollowing formulation:

[0045] 40.0% weight Stockhausen 63815 superabsorbent polyacrylateprecursor solution;

[0046] 7.5% weight Witcobond W320polyurethane film-forming polymer;

[0047] 2.0% weight Emerlube 7440, a sulfonated mineral oil availablefrom Henkel Corp.;

[0048] 2.0% weight of a 1% wt. aqueous solution of Drewfloc 270; and

[0049] 48.5% weight of deionized water.

[0050] The composition was applied to glass fiber reinforcement strandsdesigned for use in optical cables. The reinforcements were thenimmersed in either deionized water or in a 1% wt. saline solution. Theswell rate in both the fresh water and the marine environments weredetermined by measuring the percentage swell or increase in weight overtime intervals ranging from 0-20 minutes. As a comparison, strandscoated with a dry waterblocking coating using granulated polymer powderwere also immersed in both the fresh and salt-water environments for thesame period of time.

[0051] The strands coated according to this invention and immersed indeionized or fresh water showed a swell rate that was up to seven timesfaster than the swell rate for the rods coated with the dry, granulatedpolymer, within the first minute of exposure. The swell capacity or theoverall amount of swell was up to 270% higher in comparison to the drycoating. In the salt-water environment, the coating of this inventiondemonstrated a swell rate that was more than 6 times faster than the drygranulated coating within the first minute of exposure. The coating alsoshowed up to 50% more swell capacity than the dry coating.

[0052] These results clearly show that the coating solutions of thepresent invention achieve superior water absorption, andcorrespondingly, superior water resistance, when they are applied toarticles that are exposed over prolonged periods to an aqueous fresh- orsalt-water environment.

Examples 4-5

[0053] The coatings of the present invention were further investigatedto determine their efficacy when applied to reinforcing fiber materialssuch as strands or rovings. Strands of glass reinforcing fibers werecoated with the coating and the percentage swell over time, calculatedbased on the total weight of coating and fiber was measured. Incomparison, strands coated with the dry, granular coatings were alsotested to determine the swell rate of the coating. In Example 4, thereinforcements were immersed in deionized water. For Example 5, thereinforcements were exposed to a 1% wt. sodium chloride solution. Theresults obtained are included in Table 1 and 2 below: TABLE 1 Example4 - Water Absorption in Deionized Water Swell Rate^(a) (% swell/time)Time (minutes) Example 4 Comparison Sample 0  0  0 0.033 612  86 0.0833677 119 0.1666 730 168 0.25 nr¹ 210 0.333333 745 nr 0.5 751 264 0.666666754 nr 0.83333 758 nr 1 762 336 1.5 770 nr 2 778 nr 5 810 480 10 865 57520 975 650

[0054] TABLE 2 Example 5 - Water Absorption in 1% wt. Sodium ChlorideSolution (approximates marine salt water environment) Swell Rate^(a) (%swell/time) Time (minutes) Example 5 Comparison Sample 0 0 0 0.030 22538 0.0833 237 47 0.25 265 81 0.5 276 88 1 295 99 2 312 118 5 325 140 10350 142 20 415 158

[0055] It is believed that Applicants' invention includes many otherembodiments which are not herein specifically described, accordinglythis disclosure should not be read as being limited to the foregoingexamples or preferred embodiments.

We claim:
 1. An article having at least one surface covered by awater-resistant coating comprising: a water-soluble superabsorbentpolymer; optionally a viscosity modifying agent; and a binder.
 2. Anarticle according to claim 1, selected from the group consisting oftapes, mats, fabrics, rovings, fibrous strands, laminates, sheets, rodsand cables.
 3. An article according to claim 1, selected from the groupconsisting of molded articles, woven fabrics, scrims, wood and paperproducts, and construction materials.
 4. An article according to claim1, which comprises a fibrous reinforcing material.
 5. An articleaccording to claim 4, wherein the fibrous reinforcing material isselected from the group consisting of glass fibers, polymer fibers,carbon fibers, natural fibers, and blends thereof.
 6. An articleaccording to claim 5, wherein the reinforcing fibers comprise polymerfibers selected from the group consisting of aramid fibers, nylonfibers, Kevlar fibers, polyester fibers, polyethylene fibers,polypropylene fibers, and combinations thereof.
 7. An article accordingto claim 6, wherein the polymer fibers comprise aramid fibers.
 8. Awater-resistant coating comprising a superabsorbent water-solublepolymer, wherein the superabsorbent polymer is obtained as an aqueoussolution of a polymer precursor and cured to form a superabsorbentpolymer.
 9. The water-resistant coating of claim 8, wherein thesuperabsorbent water-soluble polymer, after curing, absorbs up to about400 times its initial dry weight in water when immersed in an aqueousenvironment, and desorbs water when the coating is dried.
 10. Thewater-resistant coating of claim 8, wherein the coating has a swell rateof from about 50 grams of deionized water per gram of dry coating toabout 340 grams of deionized water per gram of dry coating, in the firstminute.
 11. The water-resistant coating of claim 8, wherein the coatinghas a swell rate of from about 33 grams of salt water per gram of drycoating to about 66 grams of salt water per gram of dry coating, in thefirst minute.
 12. The water-resistant coating of claim 9, wherein thecoating has a swell rate of about 126 grams of water per gram of drycoating, and about 50 grams of salt water per gram of dry coating, inthe first minute.
 13. An article comprising the water resistant coatingof claim
 9. 14. An article comprising the water resistant coating ofclaim
 11. 15. An article comprising the water-resistant coating of claim12.
 16. A method of providing water resistance to the surface of anarticle comprising: a) preparing a liquid coating composition comprisinga water-soluble superabsorbent polymer precursor and a viscositymodifying agent; b) applying the liquid coating composition to thesurface of the article to form a liquid coating; and c) drying andcuring the liquid coating to form a water-absorbing, water-resistantcoating layer comprising a superabsorbent polymer on the surface of thearticle.
 17. The method of claim 16, wherein the step of applying theliquid coating composition to the surface of the article comprisescontacting the liquid coating composition with the surface of thearticle to form a layer of liquid coating over the entire surface of thearticle.
 18. A method of providing corrosion resistance to the surfaceof an article comprising: a) preparing a liquid coating compositioncomprising a water-soluble superabsorbent polymer precursor and aviscosity modifying agent; b) applying the liquid coating composition tothe surface of the article to form a liquid coating; and c) drying andcuring the liquid coating to form a water-absorbing, corrosion-resistantcoating layer comprising a superabsorbent polymer on the surface of thearticle.